This study aims to test the acute and subchronic effects of nicotine in relieving some of the cognitive symptoms of Alzheimer's disease and cognitive and motor symptoms of Parkinson's disease. Since the initiation of this project in the summer of 1996, considerable progress has been made. We experienced some delays due to the inability of a software/hardware developer to provide the ordered software and hardware in a timely manner and in recruitment of patients. However, these problems have been solved, and we are preceding rapidly with the clinical phase of the project. We have currently recruited and successfully screened 11 Parkinson's disease patients for our current study. The patients have tolerated the drug administration well and no unusual or problematic physical or behavioral side effects have been encountered except in one patient who had to be taken off the chronic phase of the study due to poor tolerance. We have analyzed the acute and chronic phase data from nine patients thus far. The data show clear dose-related effects on a number of cognitive operations including motor transit time, internal processing, arousal, motor tracking and the Stroop effect. Further, chronic phase data suggest long-lasting effects on motor functioning. Plans include: 1) Completion of the Parkinson's disease component; 2) Completion of the Alzheimer's disease component; 3) Data analysis. We anticipate being behind schedule (approximately 6-9 months) for the completion of the Alzheimer's disease component of this project, because of extremely slow Alzheimer's disease patient recruitment.